/**
 * 接收者，实际执行命令的类
 */
public class Stock {
     
   private String name = "ABC";
   private int quantity = 10;
 
   public void buy(){
      System.out.println("Stock [ Name: "+name+", Quantity: " + quantity +" ] bought");
   }
   public void sell(){
      System.out.println("Stock [ Name: "+name+", Quantity: " + quantity +" ] sold");
   }
}
